Use of a galvanic couple as the power source in iontophoresis devices is well known in the art. See, e.g., U.S. Pat. Nos. 5,147,297, 5,162,043, 5,298,017, 5,326,341, 5,405,317, 5,685,837, 6,584,349, 6,421,561 and 6,653,014. Typical materials from which a galvanic couple is made include a silver/zinc donor electrode and a silver/silver chloride counter electrode. Such a combination produces an electric potential of about one volt and activates automatically when body tissue and/or fluids form a complete circuit with the system to generate the electricity.
U.S. Patent Application Publication No. US2007/0060862 discloses galvanic couple-containing devices for treating various tissues and conditions. In one embodiment, such devices may comprise two dissimilar conductive electrodes in a carrier layer connected to each other either through a connective wire or by direct physical contact to form a plurality of galvanic couple power sources. As shown in FIGS. 8-11, the conductive electrodes are in the form continuous structures (such as zinc wire) spanning the carrier layer that touch each other or a connecting wire at several locations.
U.S. Pat. No. 7,457,667 and US Patent Application Publication Nos. US2006/0015052 and US2006/0015053 disclose wound dressings that are said to employ galvanic currents. The wound dressings comprise substrate materials holding areas or particles of two dissimilar metals, such areas or particles in proximity but not touching each other.
Applicants have now discovered improved galvanic skin treatment devices comprising a plurality of discrete galvanic couples that comprise conductive electrodes in electronic communication with one another on a substrate. Such galvanic couples are detached from each other, generally of a small size, and of variable shape and positioning on the substrate. In one embodiment, the substrate is made of paper.
Advantageously, use of a plurality of galvanic couples on the substrate, i.e., a galvanic couple array, enables the tailored and controlled distribution of multiple positive and negative poles over a treatment area and consequently a very uniform electricity distribution to the tissue under treatment. This is not possible with conventional electrical devices that offer only one anode and one cathode, or devices that contain scattered metallic particles. Because each galvanic couple acts independently of surrounding ones, each galvanic couple exclusively treats the skin directly adjacent to it. Therefore, a plurality of galvanic couples provides a uniformly distributed dose of electricity to the treatment area. Another advantage of this effect is that the maximum dose of electricity is controlled by the output of each galvanic couple. This is particularly advantageous if a portion of the treatment area has varying conductivity or compromised skin integrity, such as with a wound (e.g. the maximum current supplied is limited to that provided by the local galvanic couples only). The present device also enables flexibility for a user in terms of shape and size. For example, a nurse can produce a desirably sized and shaped wound dressing to fit a chronic wound/lesion (which might be of any shape or size) from a device of the invention without disabling the galvanic couples.